We have defined pregnancy-associated mortality as death of an adult monkey during pregnancy, during delivery, or from complications following delivery. Pregnancy-associated deaths occur at the rate of 3% of all pregnancies within the colony and are the leading cause of death within adult females. Dystocia occurs in 50% of pregnancy-associated deaths. Monkeys at risk for pregnancy-associated death are usually feral, multigravida and aged. This profile differs from those monkeys which are most likely to experience dystocia: colony-born, primigravida, and young. In 1996, there was one pregnancy-associated death in a middle-aged, multigravida, colony-born monkey #1216. The monkey had marked left ventricular hypertrophy and died shortly after parturition.